PS 7 Chem 101 Spring 2025 2

Problem Set Overview

General Information

  • Course: Chem 101

  • Problem Set: 7

  • Semester: Spring 2025

  • Name line for student: ______________________________________

Electron Configuration Questions

  1. Write the most stable electron configuration for:

  • (a) Sulfur (S, Z=16)

    • Configuration: [Ne] 3s² 3p⁴

  • (b) Technetium (Tc, Z=43)

    • Configuration: [Kr] 5s² 4d⁵

  • (c) Silver (Ag, Z=47)

    • Configuration: [Kr] 5s¹ 4d¹⁰

Electron Configuration for Ions

  1. Electron configuration for Rh³⁺

    • Configuration: [Kr] 4d⁵

    • Note: Transition metals lose outermost s-electrons first.

Ionization Energy Change

  1. Change in electron configuration associated with the first ionization energy of Aluminum (Al)

  • Option (a): [Ne] 3s²3p¹ → [Ne] 3s¹3p¹ + e⁻

  • This represents the removal of one electron.

Partial Orbital Diagrams

  1. Identify neutral atom and +2 ion using the orbital diagram:

  • (a) represents a neutral atom, (b) is a +2 ion.

Periodic Trends

  1. Order elements by increasing atomic radius (smallest to largest):

  • Elements: Cs, Rb, Sr

  • Order: Sr < Rb < Cs

  1. Order elements by increasing ionization energy (least to greatest):

  • Elements: Al, B, C

  • Order: Al < B < C

  1. Order elements by increasing electron affinity (least to greatest):

  • Elements: I, Rb, Cl

  • Order: Rb < I < Cl

  1. Circle the atom or ion with larger radius in each pair:

  • (a) Ne vs Kr: Kr

  • (b) P vs P³⁻: P³⁻

  • (c) Al vs Al³⁺: Al

  • (d) Na⁺ vs F⁻: F⁻

  • (e) Cu⁺ vs Cu²⁺: Cu⁺

  • (f) O²⁻ vs S²⁻: S²⁻

Unpaired Electrons

  1. Count unpaired electrons and identify paramagnetic atoms:

  • Molybdenum (Mo): ____

  • Nitrogen (N): ___

  • Vanadium (V): ____

  • Oxygen anion (O¹⁻): ___

  • Vanadium cation (V³⁺): ____

Additional Electron Configuration Questions

  1. Change in electron configuration associated with the electron affinity of Aluminum (Al):

  • Option (c): [Ne] 3s²3p¹ + e⁻ → [Ne] 3s²

  1. Count the number of valence electrons for each element:

  • Barium: 2

  • Phosphorus: 5

  • Lithium: 1

  • Germanium: 4

  • Iodine: 7

  • Sulfur: 6

  • Al²⁺: 3

  • Cl⁻: 8

  1. Identify the main group element in Period 4 based on its valence shell orbital diagram:

  • Symbol:

  1. Existence of an atom with a specific orbital diagram:

  • Can it exist?

  • If yes, symbol for the element:

  1. Symbol and charge for the following cases:

  • (a) Element that lost one electron:

  • (b) Element that gained two electrons:

  1. Cation formation by losing one electron:

  • Circle the electron to be lost:

  • Cation symbol and charge:

  1. Identify the elements for the given electron configurations:

  • (a) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d⁵:

  • (b) [Xe]6s²4f¹⁵5d¹⁰6p⁵:

  • (c) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s¹4f¹⁵5d¹⁰:

  • (d) [Rn]7s²5f⁷6d¹:

  1. Quantum numbers for 17 electrons of Chlorine (Cl):

  • (Completed example) 1, 0, 0, ½

  • Remaining configurations:

  • [Ne] 3s² 3p³

  • Quantum numbers for remaining electrons as listed.